1. Field of the Invention
The present general inventive concept relates to a transfer apparatus and an image forming device having the same.
2. Description of the Related Art
In general, an image forming apparatus, such as a copier, a printer, a facsimile, and a multi function machine embodying functions of the copier, printer, and facsimile as a single device, has a function, which prints an image on a printing medium. Such an image forming apparatus includes a feeding unit to feed the printing medium, a developing unit to develop an image on an photoconductive medium, a transfer apparatus to transfer the developed image onto the printing medium, a fixing unit to fix the transferred image, and a discharging unit to discharge the printing medium to the outside. Among these units, an example of the transfer unit is illustrated in FIG. 1.
Referring to FIG. 1, a transfer apparatus of a general image forming device includes a transfer belt 10, which is supported and rotated by a pair of rollers 21 and 22. The transfer belt 10 receives an image from a photoconductive medium and transfers the received image onto a printing medium while being rotated. At this time, one of the pair of rollers 21 and 22 is a driving roller 21, which receives a driving force from a driving source, and the other is an idle roller 22. The idle roller 22 at both ends is supported by an elastic member 30 to apply a tension to the transfer belt 10.
However, the transfer belt 10 generates a shaking or floating movement in an axial direction of the idle roller 22 in rotation. Such a floating movement of the transfer belt 10 in rotation causes a transfer quality to deteriorate.
To address such a problem, a method, which forms the idle roller 22 in the form of a crown in which a center and both ends thereof have deferent diameters, or forms a guide projection and a guide groove on an inner side surface of the transfer belt 10 and in a portion of the idle roller 22 corresponding to the guide projection, respectively, was proposed. However, as shapes of the idle roller 22 and/or the transfer belt 10 are changed, a problem occurs, in that fabrication costs are increased and a friction at specific portions is increased to cause the specific portions to wear.
Also, a conventional method has been used for additionally installing a separate sensing means and a separate compensating means capable of sensing the movement of the transfer belt 10 and compensating for it. However, fabrication costs for additionally installing the separate sensing means and a separate compensating means are increased.